Retaining walls are commonly used in landscaping and construction projects where some differential level of the adjacent soil is required. It is well known that relatively high differential pressures are thereby created on the opposite sides of such walls, requiring relatively great strength in order to support such loads. In addition, certain industries require specialized structures which must provide much the same characteristics as those generally required for retaining walls. An example is the rairroad industry, in which closed or semi-closed cribs are constructed in order to elevate components such as electrical transformers and the like. These cribs are generally filled with a relatively coarse aggregate, similar to the material used in the construction of the bedding used for support of the rails and ties.
Essentially two types of construction have been developed for such walls: The formation of a cast concrete wall on the construction site, or the construction of the wall from precast components. The casting of such a wall on the site requires retaining forms for the concrete to be constructed and some time for the poured concrete to cure, as well as the addition of reinforcing bars ("rebars") to the concrete before it is cured. This is a relatively labor and time intensive process. Alternatively, such walls are commonly constructed from precast units which may be rapidly assembled to form the required wall.
While precast systems for retaining walls have been developed which comprise a relatively few differently shaped components, these systems do not readily lend themselves to use in the construction of cribbing walls due to the corners involved in such construction. In order to achieve the required strength at the corners of such crib walls, it has heretofore been necessary to form additional more complex shapes which require additional casting forms and thereby raise the overall cost of walls constructed of such a relatively large variety of differently shaped units.
The need arises for a precast construction system utilizing a relatively small number of different shapes and sizes of precast concrete forms. The system must provide the asymmetrical strength required of such retaining or crib walls, while at the same time providing a secure and interlocking corner construction in order to achieve essentially the same strength as the remainder of the wall.